P-90: The Effect of Doping to MgO Protection Layer on Secondary Electron Emission Property

Abstract

We investigated the effect of doping to MgO protection layer on secondary electron emission properties. The firing voltage of ZnO doped (1 at. %) MgO is lower by 40V than that of non‐doped MgO at 4.2 Torr cm. Li2O (1 at. %) and BaO (1 at. %) doped MgO also shows lower firing voltage than non‐doped MgO about 20V.

Mixed Films Based on MgO for Secondary Electron Emission Application: General Trends and MOCVD Prospects

“…In terms of isovalent and heterogeneous isomorphism, the dissolved oxides with valence lower than MgO should provide the largest effect in generation of the Fs defects in MgO lattice. The experiment with alkaline metal oxides support well this idea: in the mixed MgO films, the F and F + defects detected by cathode-luminescent technique were of main source of reducing initial firing voltage and increasing conductivity of the films [30][31][32][33]. For two-valent oxides, low solubility as ≤1 at.% (more often it is the detection limit rather than the real magnitude) and isovalence solid substituting could not radically alter the oxygen vacancy amount and only lowering EA via surface structural modification was taken to explain the SEEC change [34,36].…”

“…The oxides of different valence were tested in the search of the best effect on SEE properties of pure MgO. This was arranged by addition of alkaline metal oxides [30][31][32][33], alkaline-earth-metal oxides [34], transition metal oxides [35][36][37][38], rare earth oxides [39][40][41][42][43][44][45] and others [46][47][48][49]. The surprising thing was that results of all the studies after the additives showed a certain enhancement of SEE properties of MgO relate to the pure MgO although often this effect remained without any explanation.…”